Phosphorus-containing compounds useful for making halogen-free, ignition-resistant polymers

ABSTRACT

Phosphorus-containing compounds useful for flame retardant epoxy resins are disclosed. The flame retardant epoxy resins may be used to make electrical laminates. This invention is particularly useful in end use applications in which a low bromine or low halogen content is required or desired.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Division of application Ser. No. 13/790,136 filedMar. 8, 2013; which is a Division of application Ser. No. 13/462,876filed on May 3, 2012, application Ser. No. 13/462,876 is a Divisionapplication of Ser. No. 12/939,725 filed on Nov. 4, 2012 is a Divisionof application Ser. No. 11/587,119 filed on Oct. 20, 2006, which is a371 of PCT/US05/17954 filed on May 20, 2005.

The present invention is in the field of phosphorus-containingcompounds; their use as flame retardants for polymers, especially forepoxy, polyurethane, thermosetting resins and thermoplastic polymers;and the use of such flame retardant-containing polymers to makeprotective coating formulations and ignition-resistant fabricatedarticles, such as electrical laminates, polyurethane foams, and variousmolded and/or foamed thermoplastic products.

Ignition-resistant polymers have typically utilized halogen-containingcompounds to provide ignition resistance. However, there has been anincreasing demand for halogen-free compositions in ignition-resistantpolymers markets. Proposals have been made to use phosphorus-based flameretardants instead of halogenated fire retardants in thermoset epoxyresin formulations as described in, for example, EP A 0384939, EP A0384940, EP A 0408990, DE A 4308184, DE A 4308185, DE A 4308187, WO A96/07685, and WO A 96/07686.

However, further improvements in flame resistance are desired. There isalso a desire to improve the manufacture and performance of theignition-resistant polymer composition.

Therefore, there remains a need to provide a halogen-free polymercomposition having good ignition-resistance and heat resistance; andwhich overcomes the disadvantages of prior art compositions whichexhibit poor properties such as poor moisture resistance and low Tg.

One aspect of the present invention is directed to a process for makinga phosphorus-containing compound comprising reacting:

-   -   (A) at least one organophosphorus compound having a group        selected from the group H—P═O; the group P—H and the group P—OH        with    -   (B) at least one compound having the following Formula (I):

[R′(Y)_(m′)]_(m)(X—O—R″)_(n)  Formula (I)

-   -   -   wherein        -   R′ is an organic group;            -   Y is a functional group selected from the group                consisting of hydroxy, carboxylic acid, and amine;        -   X is a hydrocarbylene group;        -   R″ is hydrogen or a hydrocarbyl group having from 1 to 8            carbon atoms;        -   R is alkyl or aryl group having from 1 to 12 carbon atoms;            and        -   m′, m and n are, independently, numbers equal to or greater            than 1.

Another aspect of this invention is directed to phosphorus-containingcompounds obtainable according to the above process (herein referred toas “Compound (I)”), particularly phosphorus-containing compoundscomprising the reaction product of:

-   -   (A) at least one organophosphorus compound having a group        selected from the group H—P═O, the group P—H and the group P—OH;        and    -   (B) at least one compound having the following Formula (I):

[R′(Y)_(m′)]_(m)(X—O—R″)_(n)  Formula (I)

wherein

-   -   R′ is an organic group;        -   Y is a functional group selected from the group consisting            of hydroxy, carboxylic acid, and amine;    -   X is a hydrocarbylene group;    -   R″ is hydrogen or a hydrocarbyl group having from 1 to 8 carbon        atoms, R is alkyl or aryl group having from 1 to 12 carbon        atoms; and        m′, m and n are, independently, numbers equal to or greater than        1.

More particularly, the phosphorus containing compounds are those havingat least two phenolic aromatic rings preferably linked by ahydrocarbylene group or hydrocarbylene ether group and a phosphoruscontent of at least 4 wt-percent.

Other aspects of the present invention include for example compounds,compositions and/or formulations obtainable by reacting, blending ormixing Compound (I) with other components such as a thermosetting resinor a thermoplastic material or a mixture of a thermosetting resin and athermoplastic material to form various ignition resistant compounds,compositions or formulations useful in various applications such asprepregs, laminates, coatings, molding articles and composite products.

For example, one aspect of the present invention is directed tophosphorous-containing epoxy compounds obtainable by reacting at leastone of the above phosphorus-containing compounds (Compound (I)) with atleast one compound having one epoxy group per molecule, for example,epichlorohydrin, glycidylether of polyphenols (such as bisphenol A,Bisphenol F, phenol novolac, cresol phenol novolac), glycidylether ofmethacrylate, glycidylether of acrylate and other similar compounds.Such phosphorus-containing epoxy compounds may also be combined with atleast one curing agent, and optionally at least one crosslinkable epoxyresin other than the phosphorus-containing epoxy compound, to obtaincurable ignition-resistant epoxy resin compositions. Such epoxy resincompounds and phosphorus-containing epoxy compounds may be used to makeprepregs, which may be used to make laminates and circuit boards usefulin the electronics industry. The epoxy compounds may also be used tocoat metallic foils such as copper foils to make resin coated copperfoils for a so call build up technology.

Another aspect of the present invention is directed tophosphorous-containing epoxy resin curable formulations comprising (i)Compound (I), (ii) an epoxy resin or a mixture of epoxy resins, (iii)optionally, a co-crosslinker, (iv) optionally, a catalyst, and (v)optionally, a Lewis acid.

A further aspect of this invention is directed to benzoxazinegroup-containing compounds obtainable by reacting (i) at least one ofthe above phosphorus-containing compounds (Compound (I)) having aphenolic functionality or an amine functionality with either (ii) aprimary amine and a formaldehyde or (iii) a hydroxyl-containing compoundand a formaldehyde to form a phosphorus-containing benzoxazine compound.Also useful in the present invention are benzoxazine compounds that forma polybenzoxazine upon heating.

Yet another aspect of the present invention is directed to curableflame-resistant epoxy resin compositions comprising (i) the abovephosphorus-containing benzoxazine-containing compound, (ii) acrosslinkable epoxy resin or a blend of two or more epoxy resins havingmore than one epoxy group per molecule, (iii) optionally a curing agentand, (ii) optionally, a curing catalyst to obtain a curable flameresistant epoxy resin composition. Such curable flame resistant epoxyresin compositions may be used to make prepregs, which may be used tomake laminates and circuit boards useful in the electronics industry.The epoxy resin composition may also be used to coat metallic foils suchas copper foils to make resin coated copper foils for a so call build uptechnology.

Another aspect of the present invention is directed to the thermolabilegroup-containing phosphorus-containing compounds obtainable by reacting(i) at least one of the above phosphorus-containing compounds, Compound(I), having a phenolic functionality with (ii) a thermolabilegroup-containing compound such as a compound having t-butyloxycarbonylgroups to form a modified phosphorus-containing compound. The modifiedphosphorus-containing compounds are stable at ambient temperature andits thermolabile groups degrade at elevated temperature leading to gasgeneration. These modified phosphorus-containing compounds can beblended with different thermosetting systems to generate gas bubblesleading to encapsulation of gas in the crosslinked systems having lowerdielectric constant and loss factor or products having lower weight whenthe processing temperature is well controlled.

Yet another aspect of this invention is directed to polyols obtainableby reacting (i) at least one of the above phosphorus-containingcompounds, Compound (I), with an (ii) ethoxy and/or a propoxy group.Such polyols are useful intermediates for making ignition-resistantpolyurethane resins.

The phosphorus-containing compounds, Compounds (I), according to thisinvention, and derivatives thereof, may also be combined with at leastone thermoplastic resin to make an ignition-resistant thermoplasticcomposition.

The phosphorus-containing compounds, Compounds (I), according to thisinvention, and derivatives thereof, may also be combined with at leastone thermoplastic resin and thermosetting systems (epoxy and curingagents) to make an ignition-resistant thermoplastic containingthermosetting compositions.

Other aspects of the present invention are evident from the detaileddescription and claims which follow.

DEFINITIONS

The terms “organo” and “organic” as used herein refer to compounds ormoieties comprising carbon atoms and hydrogen atoms, and optionallyhetero atoms (that is, atoms which are not carbon or hydrogen), whichare primarily covalently bonded to one another. Preferred optionalhetero atoms include oxygen atoms and nitrogen atoms. The number ofhetero atoms in the “organo” and “organic” compounds and moieties isless than the number of carbon atoms, and is preferably less than halfthe number of carbon atoms.

The terms “hydrocarbyl” and “hydrocarbylene” refer to chemicalstructures or moieties comprising carbon atoms and hydrogen atomscovalently bonded to each other. Such structures or moieties may containatoms other than, and in addition to, carbon and hydrogen (referred toherein as “hetero” atoms) insofar that the hetero atoms do not addsignificant reactive functionality to such moieties. An example of suchacceptable hetero atoms are ether oxygen atoms. Such moieties preferablydo not contain any hetero atoms.

The expression “substantially free”, as that expression is used hereinwhen used with reference to a particular substance, means that astarting material or product generally contains less than 10 weightpercent, preferably less than 5 weight percent, more preferably lessthan 1 weight percent, and more preferably zero weight percent, of aparticular substance.

The expression “wt. percent” means “weight-percent”.

Phosphorus—Containing Compound, Compound (I)

The phosphorous-containing compound of the present invention, hereinreferred to as Compound (I), is obtainable from the reaction between theorganophosphorus compound, herein referred to as Component (A), and thecompound of Formula (I), herein referred to as Component (B). One of theadvantages of Compound (I) is that it contains a phosphorus element inits chemical structure making it useful as a raw material for preparingflame resistant materials. Another advantage of Compound (I) is that ithas an active hydrogen group making it useful as a reactive startingmaterial for reacting with other polymers. For example, Compound (I) maycontain active hydrogen groups such as hydroxyl groups which makes itreactive with epoxy resins. In this embodiment, Compound (I) can beconsidered as a crosslinking agent, curing agent or hardener for anepoxy resin.

Compound (I) generally has a phosphorous content of at least 4wt-percent and preferably at least 6 weight-percent make it useful as aflame retardant material. Compound (I) is preferably substantially freeof bromine atoms, and more preferably substantially free of halogenatoms. Compound (I) may also be used as a non-reactive additive, such aswhen used with a thermoplastic or other thermosetting systems. Forexample, Compound (I) can be used a charring agent to provide aninsulating layer of char at elevated temperatures for thermoplasticformulations and for thermosetting formulations.

Compounds Corresponding to Formula (I), Component (B)

Compounds which fall within the scope of Formula (I) as described aboveare also referred herein as Component (B).

In Formula (I), each (—X—O—R″) group may be bonded to the same ordifferent atom in “R′”. Preferably, each (—X—O—R″) group is bonded to adifferent atom in “R′”.

“X” preferably has from 1 to 8, and more preferably from 1 to 4, carbonatoms. In a preferred embodiment, “X” is an alkylene group having from 1to 8, preferably from 1 to 4, and even more preferably 1 or 2, carbonatoms, such as methylene, ethylene, propylene, isopropylene, butylene,isobutylene. Methylene is the most preferred “X” group.

“R″” may be a hydrogen atom or a hydrocarbyl group having 1, preferablyat least 2, and more preferably at least 3, carbon atoms; and preferablyup to 20, more preferably up to 12, and up to 6, and even morepreferably up to 5, carbon atoms. The hydrocarbyl group is preferably analkylene group, such as methyl, ethyl, propyl, isopropyl, butyl,isobutyl, pentyl, hexyl, heptyl, and octyl. Most preferred for the R″group are methyl, butyl and isobutyl.

“R′” preferably comprises at least one arylene group and optionally atleast one hydrocarbylene group or hydrocarbylene ether group. The “R′”group more preferably comprises at least two aromatic groups linked toeach other by a hydrocarbylene group or hydrocarbylene ether group. Thearomatic groups are preferably phenyl groups and the hydrocarbylenegroup is preferably “X” as defined above, most preferably a methylenegroup and the hydrocarbylene ether is preferably a methylene oxy group.

“Y” is a functional group capable of reacting with an epoxy group, anethoxy group or a propoxy group. The “Y” functional groups arepreferably selected from hydroxyl (—OH), carboxylic acid (—C(O)OH),carboxylate (—C(O)OR′″), carboxylic acid anhydride, a primary or asecondary amine (—NH₂, —NHR″″ or ═NH, wherein “═” refers to two covalentbonds to the same or different atoms of “R′”), —SH₅, —SO₅H,—CONH₂—NHCOOR, and phosphinates (HO—P[R″]₂═O), or phosphites(H—P[OR″]₂═O).

“R′″” may be an alkali metal, such as Na+ or K+, or a hydrocarbyl grouphaving up to 8, preferably up to 4, and more preferably up to 2, carbonatoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl.

“R″″” is hydrogen or a hydrocarbyl group, such as an aryl group, analkyl group, or an alkaryl group, which preferably has up to 20, morepreferably up to 12, and even more preferably up to 4, carbon atoms.

The carboxylic acid anhydride is preferably selected from substituted orunsubstituted succinic anhydride, maleic anhydride and phthalicanhydride. Each substituent, when present is one or more hydrogen atomsor hydrocarbyl group, such as an alkyl group preferably having up to 12,and more preferably, up to 4, carbon atoms.

The hydroxyl, carboxylic acid and carboxylic acid anhydridefunctionalities are preferred, and the hydroxyl functionality is mostpreferred for the R″″ group.

The preferred compounds of Formula (I) are those compounds that meet theFormula (I), [R′(Y)_(m′)]_(m)(X—O—R″)_(n), and at least one (X—O—R″)group is in the middle of the backbone of the chemical structure. Forexample, preferred compounds include those that contain at least two(X—O—R″) groups on at least one of the same R′ (Y)_(m′) groups. Inaddition, the compounds that are useful in the present inventioninclude, for example, those that meet the following criteria:

-   -   (a) n is preferably greater than m; or    -   (b) when n is equal 1, then m must be greater than 3 and at        least one (X—O—R″) group is in the middle of the backbone of the        chemical structure; or    -   (c) when m is equal to 1, then n must be greater than 1; or    -   (d) when n is equal to 2, then at least one of the (X—O—R″)        groups must be in the middle of the backbone of the chemical        structure.

In Formula (I), m′ is preferably less than 10, m is preferably less than100, and n is preferably less than 200.

Preferred compounds of Formula (I) may be represented by the followingFormula (II):

[Ar(Y)_(m′)—X′]_(a)[Ar(Y)_(m′)—X]_(b)(X—O—R″)_(n)  Formula (II)

wherein each “Ar” independently is an aromatic group, preferably aphenyl group, optionally substituted with one or more groups, preferablyselected from alkyl, alkoxy, and alkanol, having 1 to 4 carbon atoms(for example, methyl, methoxy, methanol, ethyl, ethoxy, ethanol, propyl,propoxy, propanol, isopropyl, isopropanol, butyl, butoxy, butanol) suchas, for example, a tolylene and/or xylene group; at least one of the(X—O—R″) groups is on at least one of the Ar groups; “n”, “m′”, “X”,“Y”, and “R″” have the same meaning as in Formula (I); “X′” eachindependently may be X, X—O—X, or X—O—X—O—X; “a” and “b” eachindependently represent a number equal to or greater than zero, but bothcannot be zero.

In Formula (II), “a” is preferably up to 100, “b” is up to 100 and “n”is preferably up to 200.

A more preferred compound of Formula (I) may be represented by thefollowing Formula (III):

(R″—O—X)_(c)[Ar(Y)_(m′)—X—O—X]_(a)[Ar(Y)_(m′)—X]_(b)[Ar(Y)_(m′])]_(b′)(X—O—R″)_(d)  Formula(III)

Formula (III) wherein “Ar”, “m′”, “a”, “b”, “X”, “Y”, and “R″” have thesame meaning as in Formula (II); subscripts “b′”, “c” and “d” eachindependently represent a number equal to or greater than zero. InFormula (III), “c” is preferably up to 200 and “d” is preferably up to200.

The “Y” groups are preferably bonded directly to an Ar group. Examplesof preferred “Ar(Y)” include phenol, cresol, and xylenol, and thecorresponding divalent counterparts thereof.

The (X—O—R″) group in each unit with the subscripts “c” and “d” having avalue greater than zero is bonded directly to a member of an “Ar” groupof another unit in Formula (III), which has the same or different unitformula.

The units with the subscripts “a”, “b”, and “b” may be present in anyorder in a random or block configuration. Each of subscripts “a”, “b”,“b”, “c” and “d” independently are preferably at least 1. Each ofsubscripts “a”, “b”, “b”, “c” and “d” independently are preferably zero,more preferably at least 1, and even more preferably at least 5; yetmore preferably at least 10 and preferably not greater than 1000, andmore preferably not greater than 100. In one embodiment, the subscripts“a”, “b”, “b”, “c” and “d” independently are preferably not greater than50, more preferably not greater than 30, and even more preferably notgreater than 10.

Preferred compounds of Formula (I) may further be represented by thefollowing Formula (IV):

wherein “e” is an integer from 0 to 4; “f” is 1 or greater andpreferably less than 50; and m′, R″, Ar, Y, X, “a”, “b”, “c” and “d” areas defined above with reference to Formula (III).

Preferred compounds of Formula (III) may be represented by the followingformulas,

Formula (V) and Formula (VI);

wherein “R1” each independently is hydrogen or an alkyl group havingfrom 1 to 10 carbon atoms,“p” each independently represents a number from zero to 4;“a” and “b” each independently represent a number equal to or greaterthan zero;and “X”, “Y” and “R” have the same meaning as in Formula (III).

In a preferred embodiment, the compounds of Formula (III), that isComponent (B), may be prepared by first reacting (a) phenols, cresols,xylenols, biphenol-A, and/or other alkyl phenols and (b) formaldehyde,to form one or more monomeric, dimeric or higher condensation products.Subsequently, the condensation products resulting from reacting (a) and(b) above are modified by etherification, either partially or fullyetherified, with at least one monomeric alcohol. The monomeric alcoholis ROH wherein R is the same as defined above for Formula (I). Examplesof the resultant etherified products which can be used as Component (B),are for example etherified resole resins such as those described in U.S.Pat. No. 4,157,324, and U.S. Pat. No. 5,157,080.

Component (B) made by the above reaction of (a) and (b) preferablycontains low amounts of the starting raw materials such phenol, cresol,bisphenol A and formaldehyde as residual monomers in the reactionproduct (that is Component (B)) for example less than 3 wt percent,preferably less than 2 wt percent and more preferably less than 1 wtpercent.

It is preferable to use etherified resoles over non-etherified resolesas Component (B) in the present invention because etherified resoles aremore storage stable at room temperature (about 25° C.) whereasnon-etherified resoles have a tendency to undergo self condensation; andat elevated temperature, typically greater than 25° C., preferablygreater 100° C. and more preferably greater 150° C. and even morepreferably greater than 170° C., and generally less than 250° C. andpreferably less than 220° C. resoles have tendency to undergo selfcondensation rather than to react with the phosphorous compounds ofComponent (A). Thus, for the present invention, it is advantageous toselect etherified resoles as Component (B) that have a lower tendency toundergo self condensation and that tend to favor the main condensationreaction with Component (A) for example via the alkyl group R″.

An example of the preferred condensation product prepared by reacting(a) and (b) as described above is illustrated as according the followinggeneral chemical equation:

wherein “p” is an integer from 1 to 4 independently; and “R1” ishydrogen or an alkyl group having from 1 to 10 carbon atomsindependently.

The above reaction provides a mixture of different isomer condensationproducts having methylene linkage or a dimethylene ether linkage such as(1) having two CH₂OH (one on each benzene ring; or (2) having one CH₂OHgroup on one benzene ring.

The CH₂OH groups in the above condensation products illustrated in theabove general chemical equation are partially or fully etherified withan alcohol to provide Component (B) useful in the present invention. Inthis embodiment a mixture of different isomers of the condensationproduct can be formed.

The number average molecular weight of the compounds of Formulas (I) to(IV) is preferably at least 50, more preferably at least 200, and evenmore preferably at least 500; and is preferably not greater than 10,000,more preferably not greater than 8,000, and even more preferably notgreater than 5000. The weight average molecular weight is preferably atleast 100, more preferably at least 400, and even more preferably 1000;and is preferably not greater than 15,000, more preferably not greaterthan 3,000, and even more preferably not greater than 1,500.

Component (B) is preferably substantially free of bromine atoms, andmore preferably substantially free of halogen atoms.

An example of Component (B) is shown in the following chemical Formula(VII):

wherein “R2” each independently is hydrogen, an alkyl group having from1 to 10 carbon atoms, CH₂OH, or CH₂OR″;“R1” each independently is hydrogen or an alkyl group having from 1 to10 carbon atoms;“R″” is a hydrogen or a hydrocarbyl group having from 1 to 8 carbonatoms; and“b” represents a number equal to or greater than zero.

Other examples of Component (B) are shown in the following chemicalformulas, Formula (VIII) and Formula (VIIIa):

wherein “R2” each independently is hydrogen, an alkyl group having from1 to 10 carbon atoms, CH₂OH, or CH₂OR″;“R1” each independently is hydrogen or an alkyl group having from 1 to10 carbon atoms;“R″” is a hydrogen or a hydrocarbyl group having from 1 to 8 carbonatoms; and“a” represents a number equal to or greater than zero.

Still other examples of Component (B) are shown in the followingchemical formulas Formula (IX) and Formula (IXa):

wherein “R″” is a hydrogen or a hydrocarbyl group having from 1 to 8carbon atoms; “b” represents a number equal to or greater than zero; and“p” represents a number equal to or greater than zero.

Examples of commercially available products suitable for use asComponent (B) include SANTOLINK™ EP 560, which is a butyl etherifiedphenol formaldehyde condensation product and PHENODUR™ VPR 1785/50,which is a butoxymethylated phenol novolac which the manufacturercharacterizes as a highly butyl etherified resole based on a cresolmixture with a weight average molecular weight from 4000 to 6000 and apolydispersity from 2 to 3. Both of these products are available fromUCB Group, a company headquartered in Brussels, Belgium, and itsaffiliate, UCB GmbH & Co. KG, a company incorporated in Germany. Otherresole compounds available from UCB include for example PHENODUR PR 401,PHENODUR PR 411, PHENODUR PR 515, PHENODUR PR 711, PHENODUR PR 612,PHENODUR PR 722, PHENODUR PR 733, PHENODUR PR 565, and PHENODUR VPR1775.

Other resole compounds available from Bakelite include for exampleBAKELITE PF 0751 LA, BAKELITE PF 9075 DF, BAKELITE 9900LB, BAKELITE 9435LA, BAKELITE 0746 LA, BAKELITE 0747 LA, BAKELITE 9858 LG, BAKELITE 9640LG, BAKELITE 9098LB, BAKELITE 9241 LG, BAKELITE 9989 LB, BAKELITE 0715LG, BAKELITE 7616 LB, and BAKELITE 7576 LB.

Organophosphorus-Containing Compounds, Component (A)

The organophosphorus-containing compound, Component (A), may be selectedfrom compounds having a group selected from H—P═O, P—H, and P—OH eachsingle “—” of the groups or each “—” of “═” referring to a bond betweenthe phosphorus atom “P” and an organic moiety. The phosphorus atom maybe bonded to two separate organic moieties or may be bonded to oneorganic moiety. When bonded to one organic moiety, the bonds may connectwith the same atom of the organic moiety to form a double bond or,preferably, may be single bonds connecting the phosphorus atom withdifferent atoms in the same organic moiety.

The organophosphorus-containing compound preferably corresponds to thefollowing Formulas (X) through (XXII):

wherein “R^(A)” and “R^(B)” may be the same or different and areselected from substituted or unsubstituted aryl or aryloxy groups andhydroxyl groups provided that not more than one of R^(A) and R^(B) is ahydroxyl group, and “R^(C)” and “R^(D)” may be the same or different andare selected from hydrocarbylene and hydrocarbenylene. R^(C) and R^(D)are preferably each independently, more preferably both, an arylenegroup.

Phenylphosphine is an example of Formula (XIV), diphenyl or diethylphosphite or dimethylphosphite is an example of Formula (XV),phenylphosphinic acid (C₆H₅)P(O)(OH)H is a an example of Formula (XVI),phenylphosphonic acid (C₆H₅)P(O)(OH)₂ is an example of Formula (XVII),and dimethylphosphinic acid (CH₃)₂P(O) OH is an example of Formula(XVIII).

In a preferred embodiment, the organophosphorus-containing compound,Component (A), corresponds to one of the following chemical Formulae(XXIII) to (XXVIII):

wherein each R¹ to R⁸ is, independently, a hydrogen atom or ahydrocarbyl group that optionally may contain one or more heteroatomssuch as O, N, S, P, or Si, provided that not more than 3 of R¹ to R⁴ arehydrogen atoms and two or more of R¹ to R⁸ may be joined to one anotherto form one or more cyclic groups. The total number of carbon atoms inR¹ to R⁸ is preferably in the range from 6 to 100.

In a more preferred embodiment, the organophosphorus-containingcompound, Component (A), corresponds to the following Formula (XXIX):

wherein R⁹ represents H and each R¹⁰ independently represents a hydrogenatom or a hydrocarbyl group that optionally may contain one or moreheteroatoms such as O, N, S, P, or Si. Two or more of R¹⁰ may be joinedto one another to form one or more cyclic groups.

The above preferred embodiment organophosphorus-containing compounds aredescribed in more detail in EP-A-806429.

The organophosphorus-containing compound, Component (A), is preferably9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (also known as“DOP”), such as “Sanko-HCA”, which is commercially available from Sankoof Japan, or “Struktol Polydis™ PD 3710”, which is commerciallyavailable from Schill & Seilacher of Germany; dimethylphosphite,diphenylphosphite, ethylphosphonic acid, diethylphosphinic acid, methylethylphosphinic acid, phenyl phosphonic acid, phenyl phosphinic acid,dimethylphosphinic acid, phenylphosphine, vinyl phosphoric acid; ormixtures thereof.

The organophosphorus-containing compound, Component (A), is preferablysubstantially free of bromine atoms, more preferably substantially freeof halogen atoms.

Reaction of Component (A) with Component (B) to Form Compound (I)

To prepare Compound (I), Component (A) and Component (B) are firstblended or mixed together to form a reactive composition. Then asufficient temperature is applied to the reactive composition ofComponents (A) and (B) to initiate the reaction between the twocomponents to form Compound (I).

Component (A) is mixed with Component (B) in a reaction vessel and themixture is heated at an elevated temperature which is a temperature thatis preferably below the decomposition temperature of the startingmaterials. Generally, the reaction temperature is greater than 25degrees Celsius, preferably greater than 150 degrees Celsius, and morepreferably greater than 170 degrees Celsius The reaction is preferablycarried out for a period of time sufficient to a react the H—P═O, P—H,or P—OH moieties of Component (A) with the OR″ moieties of Component(B). The time of reaction is typically from 30 minutes to 20 hours,preferably from 1 hour to 10 hours, and more preferably from 2 hours to6 hours.

The reaction of the present invention is preferably carried out withoutthe presence of water (generally the water is present in less than 5 wtpercent, more preferable less than 3 wt percent and most preferable lessthan 1 wt percent) because water may tend to react with Component (A).Removal of alcohol and other volatile byproducts such as other solventsformed as a byproduct of this reaction generally helps drive thereaction to completion. The pressure in the reaction vessel is thereforepreferably reduced to a pressure below atmospheric pressure, such as apressure of 0.1 bar or less, to help drive off the alcohol or byproductsat a temperature below the above-mentioned lowest decompositiontemperature. The reaction vessel may optionally be purged with a gas orvolatile organic liquid to further assist in removing byproduct(s). Thegas or volatile organic liquid is preferably inert to the contents ofthe reaction vessel.

Component (B) is usually dissolved in an organic solvent, well know tothose skilled in the art, such as butanol, xylene, or Dowanol PM(trademark of The Dow Chemical Company); and part of the solvent can beremoved either by heat or applying vacuum to the solution before theaddition of Component (A). The order of charging of Component (A) andComponent (B) into the reaction mixture is not important.

Components (A) and (B) are preferably combined at a weight ratio in therange from 10:1 to 1:10, preferably from 5:1 to 1:5, more preferablyfrom 2:1 to 1:2, most preferably in the range from 1.1:1 to 1:1.1 basedon total solids content of the composition.

If desired, other materials such as catalysts or solvents may be addedto the reaction mixture of Component (A) and (B).

The phosphorous-containing product of the present invention, Compound(I), resulting from the reaction between Component (A) and Component (B)has a phosphorus content of preferably at least 4 weight-percent, andmore preferably at least 6 weight-percent. The phosphorus content ofCompound (I) generally ranges from 4 to 12 percent, preferably from 5 to9 and more preferably from 6 to 8 weight percent. Component (I) ispreferably substantially free of bromine atoms, and more preferablysubstantially free of halogen atoms.

Compound (I) has a Mettler softening point generally greater than 100°C. and preferably greater than 120° C.; and preferably less than 250° C.and more preferably less than 200° C. The product is preferably a solidat room temperature (about 25° C.) for better storing, shipping andhandling.

Generally, the resulting Compound (I) from the reaction of Components(A) and (B) may be a blend of one or more of different oligomers.

Ignition resistant Epoxy Resin Compositions

In one embodiment of the present invention, the phosphorus-containingcompound, Compound (I), obtainable by reacting Component (A) withComponent (B), as described above, may be used, as one component, of acurable (crosslinkable) phosphorus-containing flame resistant epoxyresin composition. In this embodiment, the curable phosphorus-containingflame-resistant epoxy resin composition comprises (i) thephosphorus-containing compound, Compound (I), according to the presentinvention, (ii) at least one epoxy resin such as those selected fromhalogen-free epoxies, phosphorus-free epoxies, brominated epoxies, andphosphorus-containing epoxies and mixtures thereof, including, but notlimited to DEN 438, DER 330 (DEN and DER are trademarks of The DowChemical Company), epoxy functional polyoxazolidone containingcompounds, cycloaliphatic epoxies, GMA/styrene copolymers, the reactionproduct of liquid epoxy resins (LER) and tetra bromo bisphenol A (TBBA)resins, DER 539, and the reaction product of DEN 438 and DOP resins; andoptionally (iii) at least one curing agent. The curable flame-retardantepoxy resin composition optionally may contain at least one additionalcrosslinkable epoxy resin or a blend of two or more epoxy resins otherthan and different from component (ii) above. The curable flameresistant epoxy resin composition may also optionally contain at leastone curing catalyst and at least one inhibitor. All of the abovecomponents may be blended or mixed together in any order to form thecurable phosphorus-containing flame-retardant epoxy resin composition.

In another embodiment, Compound (I) may be first reacted with an epoxycompound to form a phosphorus-containing epoxy compound (herein referredto as an “epoxidized Compound (I)”), and then subsequently theepoxidized Compound (I) may be combined with at least one curing agentto form the curable flame-retardant epoxy resin composition. The curableflame-retardant epoxy resin composition of this embodiment optionallymay contain at least one additional crosslinkable epoxy resin or a blendof two or more epoxy resins other than and different from the epoxidizedCompound (I). This curable flame resistant epoxy resin composition mayalso optionally contain at least one curing catalyst and at least oneinhibitor. This embodiment of the present invention directed to formingthe epoxidized Compound (I) first, has an advantage of forming a lowmolecular weight epoxy compound that can be advanced to a highermolecular weight epoxy in a subsequent step or blended with other epoxyresins. The epoxidized Compound (I) may be obtainable by reacting (i)the above phosphorus-containing compound, Compound (I) with (ii) atleast one epoxy compound having at least one epoxy group per molecule.For example, an epoxy resin having one epoxy group per molecule that canbe used in the present invention may be epichlorohydrin. Withepichlorohydrin, a lower molecular weight epoxidized Compound (I) may beobtained such as for example a resin having less than 700. In anotherembodiment, higher molecular weight epoxy resins such those havingmolecular weights of greater than 700 may be obtained by reacting (i)the above phosphorus-containing compound, Compound (I) with (ii) atleast one epoxy compound having at least one, and preferably two ormore, epoxy groups per molecule.

For example, the crosslinkable phosphorus-containing epoxy compound,epoxidized Compound (I), is obtainable by reacting the above-describedphosphorus-containing compound, Compound (I), with at least one epoxycompound having more than 1, preferably at least 1.8, more preferably atleast 2, epoxy groups per molecule, wherein the epoxy groups are1,2-epoxy groups. In general, such polyepoxide compounds are a saturatedor unsaturated aliphatic, cycloaliphatic, aromatic or heterocycliccompound which possess more than one 1,2-epoxy group. The polyepoxidecompound can be substituted with one or more substituents such as loweralkyls. Such polyepoxide compounds are well known in the art.Illustrative polyepoxide compounds useful in the practice of the presentinvention are described in the Handbook of Epoxy Resins by H. E. Lee andK. Neville published in 1967 by McGraw-Hill, New York and U.S. Pat. No.4,066,628.

The epoxidized Compound (I) which contains a phosphorus element can beused to form curable epoxy compositions with the addition of acrosslinker and, optionally, a catalyst to produce the curable flameresistant epoxy resin compositions.

The curable flame resistant epoxy resin compositions prepared accordingto the present invention whether made either by reacting a mixture ofCompound (I), an epoxy resin and a curing agent; or by reacting anepoxidized Compound (I) with a curing agent, may be used to makeprepregs, which, in turn, may be used to make laminates and circuitboards useful in the electronics industry. The curable composition mayalso be used to coat metallic foils such as copper foils to make resincoated copper foils for a so call build up technology.

Any of the epoxy resins which can be used in the above compositions topractice of the present invention include polyepoxides having thefollowing general Formula (XXX):

wherein “R3” is substituted or unsubstituted aromatic, aliphatic,cycloaliphatic or heterocyclic group having a valence of “q”, “q”preferably having an average value of from 1 to less than about 8.Examples of the polyepoxide compounds useful in the present inventioninclude the diglycidyl ethers of the following compounds: resorcinol,catechol, hydroquinone, bisphenol, bisphenol A, bisphenol AP(1,1-bis(4-hydroxylphenyl)-1-phenyl ethane), bisphenol F, bisphenol K,tetrabromobisphenol A, phenol-formaldehyde novolac resins, alkylsubstituted phenol-formaldehyde resins, phenol-hydroxybenzaldehyderesins, cresol-hydroxybenzaldehyde resins, dicyclopentadiene-phenolresins, dicyclopentadiene-substituted phenol resins tetramethylbiphenol,tetramethyl-tetrabromobiphenol, tetramethyltribromobiphenol,tetrachlorobisphenol A, and any combination thereof.

Examples of particular polyepoxide compounds useful in the presentinvention include a diglycidyl ether of bisphenol A having an epoxyequivalent weight (EEW) between 177 and 189 sold by The Dow ChemicalCompany under the trademark D.E.R. 330; the halogen-freeepoxy-terminated polyoxazolidone resins disclosed in U.S. Pat. No.5,112,932, phosphorus element containing compounds disclosed in U.S.Pat. No. 6,645,631; cycloaliphatic epoxies; and copolymers of glycidylmethacrylate ethers and styrene.

Preferred polyepoxide compounds include epoxy novolacs, such as D.E.N.438 or D.E.N. 439 (trademarks of The Dow Chemical Company); cresoleepoxy novolacs such as QUATREX 3310, 3410 and 3710 available from CibaGeigy;trisepoxy compounds, such as TACTIX 742 (trademark of Ciba GeigyCorporation of Basel, Switzerland); epoxidized bisphenol A novolacs,dicyclopentadiene phenol epoxy novolacs; glycidyl ethers oftetraphenolethane; diglycidyl ethers of bisphenol-A; diglycidyl ethersof bisphenol-F; and diglycidyl ethers of hydroquinone.

In one embodiment, the most preferred epoxy compounds are epoxy novolacresins (sometimes referred to as epoxidized novolac resins, a term whichis intended to embrace both epoxy phenol novolac resins and epoxy cresolnovolac resins). Such epoxy novolac resin compounds have the generalchemical structural formula illustrated by Formula (XXXI) as follows:

wherein “R4” is hydrogen or a C₁-C₃ alkyl, for example, methyl; and “r”is 0 or an integer from 1 to 10. “n” preferably has an average value offrom 0 to 5. The preferred epoxy novolac resin is when “R4” ispreferably a hydrogen atom in the above Formula (XXXI).

Epoxy novolac resins (including epoxy cresol novolac resins) are readilycommercially available, for example under the trade names D.E.N.(trademark of The Dow Chemical Company), and QUATREX and TACTIX 742(trademarks of Ciba Geigy). The materials of commerce generally comprisemixtures of various species of the above Formula (XXXI) and a convenientway of characterizing such mixtures is by reference to the average, r′,of the values of r for the various species. Preferred epoxy novolacresins for use in accordance with the present invention are those inwhich r′ has a value of from 0 to 10, more preferably from 1 to 5.

Additional examples of epoxy-containing compounds useful in the presentinvention are the reaction products of an epoxy compound containing atleast two epoxy groups and a chain extender as described in WO 99/00451.The preferred reaction product described in WO 99/00451 useful in thepresent invention is an epoxy-polyisocyanate adduct or anepoxy-terminated polyoxazolidone as described in U.S. Pat. No.5,112,932. The isocyanate compounds as chain extenders include forexample diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI)and isomers thereof.

The polyepoxide useful in the present invention is preferablysubstantially free of bromine atoms, and more preferably substantiallyfree of halogen atoms.

An example of polyepoxides that are useful in the present invention andthat are substantially free of halogen atoms are thephosphorus-containing epoxy resins described in U.S. Pat. No. 6,645,631.The polyepoxides disclosed in U.S. Pat. No. 6,645,631 are the reactionproducts of an epoxy compound containing at least two epoxy groups and areactive phosphorus-containing compound such as3,4,5,6-dibenzo-1,2-oxaphosphane-2-oxide (DOP), or10-(2′,5′-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOP-HQ).

As described above, a curable flame resistant epoxy resin compositionmay be formed by blending (i) the phosphorus-containing product,Compound (I), obtainable by reacting Component (A) with Component (B),(ii) at least one crosslinkable phosphorus-containing epoxy compoundprepared according to U.S. Pat. No. 6,645,631, and optionally (iii) atleast one curing agent; or the curable flame retardant epoxy resincomposition may be formed by blending (i) an epoxidized Compound (I), atleast one crosslinkable phosphorus-containing epoxy compound preparedaccording to U.S. Pat. No. 6,645,631, and (iii) at least one curingagent. The curable epoxy resin compositions may, optionally, contain atleast one crosslinkable epoxy resin other than the crosslinkablephosphorus-containing epoxy compounds in (ii) above.

Although it is preferred that the polyepoxide useful in the presentinvention be substantially free of bromine atoms, and more preferablysubstantially free of halogen atoms, in some applications a halogencontaining epoxy resin composition may be desired. In such cases, thepolyepoxide used in the present invention may be for example abrominated epoxy compound such as a brominated epoxy resin having an EEWof 400 to 450 sold by The Dow Chemical Company under the trademark ofDER 530.

With any of the compositions above where an epoxy resin is present, anynumber of crosslinking agents or co-crosslinking agents may be used.Suitable co-crosslinkers that may optionally be present in combinationwith the phosphorus-containing epoxy compounds according to the presentinvention include, for example, are the multifunctional co-crosslinkersdescribed in numerous references such as Vol. 6 Encyclopedia of Poly.Sci. & Eng., “Epoxy Resins” at 348-56 (J. Wiley & Sons 1986).

Other preferred co-crosslinkers are described in WO 98/31750.The-co-crosslinkers include, for example, copolymers of styrene andmaleic anhydride having a molecular weight (M_(w)) in the range of from1500 to 50,000 and an anhydride content of more than 15 percent.Commercial examples of these materials include SMA 1000, SMA 2000, andSMA 3000 and SMA 4000 having styrene-maleic anhydride ratios of 1:1,2:1, 3:1 and 4:1, respectively, and having molecular weights rangingfrom 6,000 to 15,000, which are available from Elf Atochem S.A.

Other preferred co-crosslinkers useful in the present invention includehydroxyl-containing compounds such as those represented by the followingFormula (XXXII):

wherein “R5” is hydrogen or an alkyl group having from 1 to 20,preferably from 1 to 10, and more preferably 2 to 5, carbon atoms and“t” is an integer of from 0 to 20, preferably from 1 to 10 and morepreferably from 2 to 5.

Commercially available products having the above Formula (XXXII)include, for example, PERSTORP 85.36.28, which is a phenolic resinobtained from phenol and formaldehyde having an average Mettlersoftening point of 103° C., melt viscosity at 150° C.=1.2 Pa·s and afunctionality of 6 to 7. Another example includes DURITE SD 1731 fromBorden Chemical of USA.

Other phenolic functional materials include compounds which form aphenolic crosslinking agent having a functionality of at least 2 uponheating. Some examples of these compounds are benzoxazinegroups-containing compounds. Examples of compounds which form a phenoliccrosslinking agent upon heating include phenolic species obtained fromheating benzoxazine, for example as illustrated in the followingchemical equation:

wherein “u” is greater than land preferably up to about 100,000; andwherein “R6” and “R7” may be, independently and separately, the same ordifferent hydrogen, an allyl group from C₁-C₁₀ such as methyl, a C₆-C₂₀aromatic group such as phenyl or a C₄-C₂₀ cycloaliphatic group such ascyclohexane.

Examples of the above compounds also include benzoxazine ofphenolphthalein, benzoxazine of bisphenol-A, benzoxazine of bisphenol-F,benzoxazine of phenol novolac, and mixtures thereof. Other compoundsuseful in the present invention are described in WO 00/27921, and U.S.Pat. No. 6,545,631. A mixture of these compounds and Formula (XXXII) mayalso be used in the present invention.

The multi-functional phenolic crosslinker is preferably used in theepoxy resin composition in an amount of from 50 percent to 150 percentof the stoichiometric amount needed to cure the epoxy resins and morepreferably from 75 percent to 125 percent of the stoichiometric amountneeded to cure the epoxy resins, even more preferably from 85 percent to110 percent of the stoichiometric amount needed to cure the epoxyresins.

When a co-crosslinker is used in the present invention, theco-crosslinker is present in an amount to crosslink less than 40 percentof the stoichiometric amount needed to cure the epoxy resin.

Any of the curable compositions of the present invention descried abovemay comprise a catalyst. Examples of suitable catalyst materials usefulin the present invention include compounds containing amine, phosphine,ammonium, phosphonium, arsonium or sulfonium moieties or mixturesthereof. Particularly preferred catalysts are heterocyclicnitrogen-containing compounds.

The catalysts (as distinguished from co-crosslinkers) preferably containon average no more than about 1 active hydrogen moiety per molecule.Active hydrogen moieties include hydrogen atoms bonded to an aminegroup, a phenolic hydroxyl group, or a carboxylic acid group. Forinstance, the amine and phosphine moieties in catalysts are preferablytertiary amine or phosphine moieties; and the ammonium and phosphoniummoieties are preferably quaternary ammonium and phosphonium moieties.

Among preferred tertiary amines that may be used as catalysts are thosemono- or polyamines having an open-chain or cyclic structure which haveall of the amine hydrogen replaced by suitable substituents, such ashydrocarbyl radicals, and preferably aliphatic, cycloaliphatic oraromatic radicals.

Examples of these amines include, among others, 1,8-diazabicyclo(5.4.0)undec-7-en (DBU), methyl diethanol amine, triethylamine, tributylamine,dimethyl benzylamine, triphenylamine, tricyclohexyl amine, pyridine andquinoline. Preferred amines are the trialkyl, tricycloalkyl and triarylamines, such as triethylamine, triphenylamine,tri-(2,3-dimethylcyclohexyl)amine, and the alkyl dialkanol amines, suchas methyl diethanol amines and the trialkanolamines such astriethanolamine. Weak tertiary amines, for example, amines that inaqueous solutions give a pH less than 10 in aqueous solutions of 1 Mconcentration, are particularly preferred. Especially preferred tertiaryamine catalysts are benzyldimethylamine and tris-(dimethylaminomethyl)phenol.

Examples of suitable heterocyclic nitrogen-containing catalysts includethose described in U.S. Pat. No. 4,925,901. Preferable heterocyclicsecondary and tertiary amines or nitrogen-containing catalysts which canbe employed herein include, for example, imidazoles, benzimidazoles,imidazolidines, imidazolines, oxazoles, pyrroles, thiazoles, pyridines,pyrazines, morpholines, pyridazines, pyrimidines, pyrrolidines,pyrazoles, quinoxalines, quinazolines, phthalozines, quinolines,purines, indazoles, indoles, indolazines, phenazines, phenarsazines,phenothiazines, pyrrolines, indolines, piperidines, piperazines andcombinations thereof. Especially preferred are the alkyl-substitutedimidazoles; 2,5-chloro-4-ethyl imidazole; and phenyl-substitutedimidazoles, and mixtures thereof. Even more preferred areN-methylimidazole; 2-methylimidazole; 2-ethyl-4-methylimidazole;1,2-dimethylimidazole; and 2-methylimidazole and mixtures thereof.Especially preferred is 2-phenylimidazole.

Preferably, a Lewis acid is also employed in any of the curable epoxyresin compositions of the present invention described above, especiallywhen the catalyst is particularly a heterocyclic nitrogen-containingcompound.

Examples of heterocyclic nitrogen-containing catalysts, which arepreferably used in combination with Lewis acids are those described inEP A 526488, EP A 0458502, and GB A 9421405.3.

The Lewis acids useful in the present invention include for example oneor a mixture of two or more halides, oxides, hydroxides and alkoxides ofzinc, tin, titanium, cobalt, manganese, iron, silicon, aluminum, andboron, for example Lewis acids of boron, and anhydrides of Lewis acidsof boron, for example boric acid, metaboric acid, optionally substitutedboroxines (such as trimethoxyboroxine), optionally substituted oxides ofboron, alkyl borates, boron halides, zinc halides (such as zincchloride) and other Lewis acids that tend to have a relatively weakconjugate base. Preferably the Lewis acid is a Lewis acid of boron, oran anhydride of a Lewis acid of boron, for example boric acid, metaboricacid, an optionally substituted boroxine (such as trimethoxy boroxine,trimethyl boroxine or triethyl boroxine), an optionally substitutedoxide of boron, or an alkyl borate. The most preferred Lewis acid isboric acid. These Lewis acids are very effective in curing epoxy resinswhen combined with the heterocyclic nitrogen-containing compounds,referred to above.

The Lewis acids and amines can be combined before mixing into theformulation or by mixing with the catalyst in situ, to make a curingcatalyst combination.

The amount of the Lewis acid employed is preferably at least 0.1 mole ofLewis acid per mole of heterocyclic nitrogen compound, more preferablyat least 0.3 mole of Lewis acid per mole of heterocyclicnitrogen-containing compound.

The curable compositions of the present invention may optionally haveboric acid and/or maleic acid present as a cure inhibitor as describedin U.S. Pat. No. 5,308,895 and U.S. Pat. No. 5,314,720. In that case,the curing agent is preferably a polyamine or polyamide, such asdescribed in U.S. Pat. No. 4,925,901.

The curable compositions of the present invention may also optionallycontain one or more additional flame retardant additives including, forexample, red phosphorus, encapsulated red phosphorus or liquid or solidphosphorus-containing compounds, for example, “EXOLIT OP 930”, EXOLIT OP910 from Clariant GmbH and ammonium polyphosphate such as “EXOLIT 700”from Clariant GmbH, a phosphite, or phosphazenes; nitrogen-containingfire retardants and/or synergists, for example melamines, melem,cyanuric acid, isocyanuric acid and derivatives of thosenitrogen-containing compounds; halogenated flame retardants andhalogenated epoxy resins (especially brominated epoxy resins);synergistic phosphorus-halogen containing chemicals or compoundscontaining salts of organic acids; inorganic metal hydrates such asSb₂O₃, Sb₃O₅, aluminum trihydroxide and magnesium hydroxide such as“ZEROGEN 30” from Martinswerke GmbH of Germany, and more preferably, analuminum trihydroxide such as “MARTINAL TS-610” from Martinswerke GmbHof Germany; boron-containing compounds; antimony-containing compounds;silica and combinations thereof. Examples of suitable additional flameretardant additives are given in a paper presented at “Flameretardants—101 Basic Dynamics—Past efforts create future opportunities,”Fire Retardants Chemicals Association, Baltimore Marriot Inner HarbourHotel, Baltimore Md., Mar. 24-27, 1996.

When additional flame retardants which contain a halogen is used in thecomposition of the present invention, the halogen-containing flameretardants are present in amounts such that the total halogen content inthe epoxy resin composition is less than 10 wt. percent, more preferablyless than 5 wt. percent, and even more preferably less than 1 wt.percent.

When additional flame retardants which contain phosphorus are present inthe composition of the present invention, the phosphorus-containingflame retardants are preferably present in amounts such that the totalphosphorus content of the epoxy resin composition is from 0.2 wt.percent to 5 wt. percent.

The curable compositions of the present invention may also optionallycontain other additives of a generally conventional type including forexample, stabilizers, other organic or inorganic additives, pigments,wetting agents, flow modifiers, UV light blockers, and fluorescentadditives. These additives can be present in amounts of from 0 to 5weight-percent and is preferably present in amounts less than 3 weightpercent. Examples of suitable additives are also described in U.S. Pat.No. 5,066,735 and in C. A. Epoxy Resins—Second Ed. at pages 506-512(Mercel Dekker, Inc. 1988).

The curable compositions of the present invention can be produced bymixing all the components together in any order. Compositions of thepresent invention may also be produced by preparing a first compositioncomprising an epoxy resin, and a second composition comprising a curingagent. The first epoxy resin composition may contain Compound (I) and anepoxy resin; or it may be simply an epoxidized Compound (I). All otheroptional or desired components, such as a curing catalyst or inhibitor,may be present in the same composition, or some may be present in thefirst, and some in the second. The first composition is then mixed withthe second composition, and cured to produce a flame resistant epoxyresin.

The flame resistant epoxy resin is preferably substantially free ofbromine atoms, and more preferably substantially free of halogen atoms,as the expression “substantially free” is defined above.

The compositions of the present invention can be used to make compositematerials by techniques well-known in the industry, such as bypultrusion, molding, encapsulation, or coating. The present invention isparticularly useful for making B-staged prepregs, laminates, bondingsheets, and resin coated copper foils by well known techniques in theindustry, as described in the background sections of EP-A-787161 andU.S. Pat. No. 5,314,720.

Benzoxazine Ring—Containing Compounds

In another embodiment of the present invention, thephosphorus-containing product, Compound (I), obtainable by reactingComponent (A) with Component (B) may be used to make a benzoxazinering-containing compound.

In this embodiment, the benzoxazine compound is obtainable by reacting(i) the above phosphorus-containing compound, Compound (I), having aphenolic functionality with (ii) a primary amine and (iii) aformaldehyde. These phosphorus containing benzoxazine ring-containingcompounds can either:

-   -   (a) be used per se and self crosslink at elevated temperatures,        such as from 100° C. to 250° C., to form a highly crosslinkable        network which has flame resistant properties; or    -   (b) be blended with epoxy resins or other thermosetting        compositions and cured at the above elevated temperatures to        form a flame resistant hybrid crosslink network; or    -   (c) be blended with thermoplastics systems (for example,        polystyrene, polyethylene, polypropylene, polyphenylenoxides        (PPO)) to form a flame resistant hybrid crosslink network; or    -   (d) be blended with thermoplastic resin (such as PPO) and a        thermosetting resin (such as epoxy and curing agent) to form a        hybrid system.

As an illustration of the above embodiment, a benzoxazine may be formedin accordance with the following general chemical reaction:

In a similar reaction as above, the phenolic-containing Compound (I) ofthe present invention is reacted with an amine and a formaldehyde toform a benzoxazine ring-containing compound.

In another embodiment, if Compound (I) has an amine functionality, thena known phenolic compound can be reacted with the amine containingCompound (I) and a formaldehyde to form the benzoxazine ring containingcompound.

The molar ratios of the three components used in the present inventionare usually 1 mole of phenolic OH groups, 1 mole of amine groups and 2moles of formaldehyde groups as illustrated in the above generalreaction. Other ratios between the above components may be used. Amixture of different amine compounds may be used.

The amines useful in the present invention include for example aniline,n-butyl amine, 1,4-amino phenol, other primary amines, and mixturesthereof.

The phenolics useful in the present invention include for examplebisphenol A, 2-allyl phenol, 4,4′-methylene diphenol, other monophenols, and polyphenols, and mixtures thereof.

Thermolabile Group—Containing Compounds

In another embodiment of the present invention, thephosphorus-containing product, Compound (I), obtainable by reactingComponent (A) with Component (B) may be used to make a thermolabilegroup-containing compound.

In this embodiment, the phosphorus-containing compound with athermolabile group may be obtainable by reacting (i) the abovephosphorus-containing compound, Compound (I) having a phenolic or anamine functionality with (ii) a thermolabile group containing compound,such as a compound having t-butyloxycarbonyl groups. These modifiedphosphorus compounds are stable at ambient temperature and itsthermolabile groups degrade at elevated temperature such as from 100° C.to 250° C., leading to gas generation. These modified phosphoruscompounds can be blended to different thermosetting systems to generategas bubbles leading to encapsulation of gas in the crosslinked systemshaving lower dielectric constant for example 10 percent lower than itsinitial value without the modified phosphorous compound; and loss factorthat is 10 percent lower or products having lower weight for example 10weight lower when the processing temperature is well controlled asdescribed in U.S. patent application Ser. No. 10/456,127 filed June,2003 entitled “Nanoporous Laminates”.

The thermolabile group containing compounds useful in the presentinvention include for example a dicarbonate and its derivatives, acarbazate and its derivatives, and other compounds containing tert-butylcarbonate. Examples of compounds containing thermolabile group are, butnot limited to, di-tert-butyl dicarbonate, di-tert-amyl dicarbonate,diallyl pyrocarbonate, diethyl pyrocarbonate, dimethyl dicarbonate,dibenzyl dicarbonate, tert-butyl carbazate and mixtures thereof. Thetert-butyl carbonate thermolabile group is advantageously stable to manynucleophiles and is not hydrolyzed under basic conditions, but it may beeasily cleaved under mid-acidic conditions or by thermolysis.

The molar ratios of the two components used in the present invention areusually 1 mole of active hydrogen group to 1 mole of thermolabile groupto form the phosphorus-containing, thermolabile group containingcompound of the present invention.

Flame Resistant Polyurethane

In another embodiment of the present invention, thephosphorus-containing product, Compound (I), obtainable by reactingComponent (A) with Component (B) is used to make phosphorus-containingpolyols which are, in turn, useful for making flame resistantpolyurethane.

The phosphorus-containing polyols of the present invention arepreferably prepared by reacting (i) an alkylene oxide, such as ethyleneoxide, propylene oxide, butylene oxide or a combination thereof, with(ii) the phosphorus-containing compound, Compound (I), according to thepresent invention. The resultant phosphorus-containing polyol product ofthe present invention preferably has from 1 to 8, and more preferably 2to 6, active hydrogen atoms.

A catalyst may be used in the above reaction to form thephosphorous-containing polyols. Catalysis for the above reaction can beeither anionic or cationic. Suitable catalysts include KOH, CsOH, borontrifluoride, a double cyanide complex (DMC) catalyst such as zinchexacyanocobaltate, and the catalysts described in U.S. Pat. No.6,201,101.

The phosphorus-containing polyol of the present invention may be usedalone or in combination with one or more other know polyols to form abase polyol composition which may be reacted with a polyisocyanate toform a polyurethane. The properties of the final polyurethane productwill depend on the nature of the various polyols used in the polyolcomposition.

The phosphorus-containing polyol or blend thereof employed to makepolyurethane resin depends upon the end use of the polyurethane productto be produced. The molecular weight or hydroxyl number of the basepolyol may thus be selected so as to result in flexible, semi-flexible,integral-skin or rigid foams, elastomers or coatings, or adhesives whenthe polyol produced from the base polyol is converted to a polyurethaneproduct by reaction with an isocyanate, and depending on the end productin the presence of a blowing agent. The hydroxyl number and molecularweight of the polyol or polyols employed can vary accordingly over awide range. In general, the hydroxyl number of the polyols employed mayrange from 20 to 800.

In the production of a flexible polyurethane foam, the polyol ispreferably a polyether polyol and/or a polyester polyol. The polyolgenerally has an average functionality ranging from 2 to 5, preferably 2to 4, and an average hydroxyl number ranging from 20 to 100 mg KOH/g,preferably from 20 to 70 mg KOH/g. As a further refinement, the specificfoam application will likewise influence the choice of base polyol. Asan example, for molded foam, the hydroxyl number of the base polyol maybe on the order of 20 to 60 with ethylene oxide (EO) capping, and forslabstock foams the hydroxyl number may be on the order of 25 to 75 andis either mixed feed EO/PO (propylene oxide) or is only slightly cappedwith EO or is 100 percent PO based. For elastomer applications, it willgenerally be desirable to utilize relatively high molecular weight basepolyols, from 2,000 to 8,000, having relatively low hydroxyl numbers,for example, 20 to 50.

Typically, polyols suitable for preparing rigid polyurethanes includethose having an average molecular weight of 100 to 10,000 and preferably200 to 7,000. Such polyols also advantageously have a functionality ofat least 2, preferably 3, and up to 8, preferably up to 6, activehydrogen atoms per molecule. The polyols used for rigid foams generallyhave a hydroxyl number of 200 to 1,200 and more preferably from 300 to800.

For the production of semi-rigid foams, it is preferred to use atrifunctional polyol with a hydroxyl number of 30 to 80.

A flame resistant polyurethane resin is obtainable by reacting (i) atleast one phosphorus-containing polyol according to the presentinvention, alone or, optionally, in combination with one or more polyolsconventionally used to make polyurethanes other than thephosphorus-containing polyol of the present invention, with (ii) acompound having more than one isocyanate group per molecule. Theisocyanates which may be used with the polyols of the present inventioninclude aliphatic, cycloaliphatic, arylaliphatic and aromaticisocyanates and mixtures thereof. Aromatic isocyanates, especiallyaromatic polyisocyanates, are preferred.

Examples of suitable aromatic isocyanates include the 4,4′-, 2,4′ and2,2′-isomers of diphenylmethane diisocyanate (MDI), blends thereof andpolymeric and monomeric MDI blends toluene-2,4- and 2,6-diisocyanates(TDI), m- and p-phenylenediisocyanate, chlorophenylene-2,4-diisocyanate,diphenylene-4,4′-diisocyanate, 4,4′-diisocyanate-3,3′-dimehtyldiphenyl,3-methyldiphenyl-methane-4,4′-diisocyanate and diphenyletherdiisocyanateand 2,4,6-triisocyanatotoluene and 2,4,4′-triisocyanatodiphenylether andmixtures thereof. The hydrogenated products of these isocyanatecompounds can be used as well.

Mixtures of isocyanates may be used, such as the commercially availablemixtures of 2,4- and 2,6-isomers of toluene diisocynates. A crudepolyisocyanate may also be used in the practice of this invention, suchas crude toluene diisocyanate obtained by the phosgenation of a mixtureof toluene diamine or the crude diphenylmethane diisocyanate obtained bythe phosgenation of crude methylene diphenylamine. TDI/MDI blends mayalso be used. MDI or TDI based prepolymers can also be used, made eitherwith different polyols. Isocyanate-terminated prepolymers are preparedby reacting an excess of polyisocyanate with polyols, including aminatedpolyols or imines/enamines thereof, or polyamines.

Examples of aliphatic polyisocyanates include ethylene diisocyanate,1,6-hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane1,4-diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, saturatedanalogues of the above mentioned aromatic isocyanates and mixturesthereof.

The preferred polyisocyanates for the production of rigid or semi-rigidfoams are polymethylene polyphenylene isocyanates, the 2,2′, 2,4′ and4,4′ isomers of diphenylmethylene diisocyanate and mixtures thereof. Forthe production of flexible foams, the preferred polyisocyanates are thetoluene-2,4- and 2,6-diisocyanates or MDI or combinations of TDI/MDI orprepolymers made therefrom.

Isocyanate tipped prepolymer based on the phosphorus-containing polyolof the present invention can also be used in the polyurethaneformulation. It is thought that using such polyols in a polyolisocyanate reaction mixture will reduce/eliminate the presence ofunreacted isocyanate monomers. This is especially of interest withvolatile isocyanates such as TDI and/or aliphatic isocyanates in coatingand adhesive applications since it improves handling conditions andworkers safety.

For rigid foam, the organic polyisocyanates and the isocyanate reactivecompounds are reacted in such amounts that the isocyanate index, definedas the number or equivalents of NCO groups divided by the total numberof isocyanate reactive hydrogen atom equivalents multiplied by 100,ranges from 80 to less than 500, preferably from 90 to 100 in the caseof polyurethane foams, and from 100 to 300 in the case of combinationpolyurethane-polyisocyanurate foams. For flexible foams, this isocyanateindex is generally between 50 and 120 and preferably between 75 and 110.

For elastomers, coating and adhesives the isocyanate index is generallybetween 80 and 125, preferably between 100 to 110.

For producing a polyurethane-based foam, a blowing agent is generallyrequired. In the production of flexible polyurethane foams, water ispreferred as a blowing agent. The amount of water is preferably in therange of from 0.5 to 10 parts by weight, more preferably from 2 to 7parts by weight based on 100 parts by weight of the polyol. Carboxylicacids or salts are also used as blowing agents.

In the production of rigid polyurethane foams, the blowing agentincludes water, and mixtures of water with a hydrocarbon or carbondioxide, or a fully or partially halogenated aliphatic hydrocarbon. Theamount of water is preferably in the range of from 2 to 15 parts byweight, more preferably from 2 to 10 parts by weight based on 100 partsof the polyol. With excessive amount of water, the curing rate becomeslower, the blowing process range becomes narrower, the foam densitybecomes lower, or the moldability becomes worse. The amount ofhydrocarbon, the hydrochlorofluorocarbon, or the hydrofluorocarbon to becombined with the water is suitably selected depending on the desireddensity of the foam, and is preferably not more than 40 parts by weight,more preferably not more than 30 parts by weight based on 100 parts byweight of the polyol. When water is present as an additional blowingagent, it is generally present in an amount from 0.5 to 10, preferablyfrom 0.8 to 6 and more preferably from 1 to 4 and most preferably from 1to 3 parts by total weight of the total polyol composition.

In addition to the foregoing components, it is often desirable to employcertain other ingredients in preparing polyurethane polymers. Amongthese additional ingredients are surfactants, preservatives, flameretardants, colorants, antioxidants, reinforcing agents, stabilizers andfillers.

In making polyurethane foam, it is generally preferred to employ anamount of a surfactant to stabilize the foaming reaction mixture untilit cures. Such surfactants advantageously comprise a liquid or solidorganosilicone surfactant. Other surfactants include polyethylene glycolethers of long-chain alcohols, tertiary amine or alkanolamine salts oflong-chain alkyl acid sulfate esters, alkyl sulfonic esters and alkylarylsulfonic acids. Such surfactants are employed in amounts sufficientto stabilize the foaming reaction mixture against collapse and theformation of large, uneven cells. Typically, 0.2 to 3 parts of thesurfactant per 100 parts by weight total polyol (b) are sufficient forthis purpose.

One or more catalysts for the reaction of the polyol (and water, ifpresent) with the polyisocyanate can be used. Any suitable urethanecatalyst may be used, including tertiary amine compounds, amines withisocyanate reactive groups and organometallic compounds and mixturesthereof. Preferably the reaction is carried out in the absence of anamine or an organometallic catalyst or a reduced amount as describedabove. Exemplary tertiary amine compounds include triethylenediamine,N-methylmorpholine, N,N-dimethylcyclohexyl-amine,pentamethyldiethylenetriamine, tetramethylethylenediamine, bis(dimethylaminoethyl)ether, 1-methyl-4-dimethylaminoethyl-piperazine,3-methoxy-N-dimethylpropylamine, N-ethylmorpholine,dimethylethanolamine, N-cocomorpholine, N,N-dimethyl-N′,N′-dimethylisopropylpropylenediamine, N,N-diethyl-3-diethylamino-propylamine anddimethylbenzylamine. Exemplary organometallic catalysts includeorganomercury, organolead, organoferric and organotin catalysts, withorganotin catalysts being preferred among these. Suitable tin catalystsinclude stannous chloride, tin salts of carboxylic acids such asdibutyltin di-laurate, as well as other organometallic compounds such asare disclosed in U.S. Pat. No. 2,846,408. A catalyst for thetrimerization of polyisocyanates, resulting in a polyisocyanurate, suchas an alkali metal alkoxide may also optionally be employed herein. Theamount of amine catalysts can vary from 0.02 to 5 percent in theformulation or organometallic catalysts from 0.001 to 1 percent in theformulation can be used.

A crosslinking agent or a chain extender may be added, if necessary. Thecrosslinking agent or the chain extender includes low-molecularpolyhydric alcohols such as ethylene glycol, diethylene glycol,1,4-butanediol, and glycerin; low-molecular amine polyols such asdiethanolamine and triethanolamine; and polyamines such as ethylenediamine, xlylenediamine, and methylene-bis(o-chloroaniline); andmixtures thereof. The use of such crosslinking agents or chain extendersis known in the art as disclosed in U.S. Pat. Nos. 4,863,979 and4,963,399; and EP 549,120.

Especially when preparing rigid foams for use in construction, anadditional flame retardant may be included as an additive. Any knownliquid or solid flame retardant can be used with the polyols of thepresent invention. Generally such flame retardant agents arehalogen-substituted phosphates and inorganic flame proofing agents.Common halogen-substituted phosphates are tricresyl phosphate,tris(1,3-dichloropropyl phosphate, tris(2,3-dibromopropyl) phosphate andtetrakis (2-chloroethyl)ethylene diphosphate. Inorganic flame retardantsinclude red phosphorous, aluminum oxide hydrate, antimony trioxide,ammonium sulfate, expandable graphite, urea or melamine cyanurate ormixtures of at least two flame retardants. When there is a desire tominimize the amount of halogen in the formulation, the inorganic flameretardants are preferred.

The applications for polyurethane foams produced by the presentinvention are those known in the industry. For example rigid foams areused in the construction industry and for insulation for appliances andrefrigerators. Flexible foams and elastomers find use in applicationssuch as furniture, shoe soles, automobile seats, sun visors, steeringwheels, armrests, door panels, noise insulation parts and dashboards.

Processing for producing polyurethane products are well known in theart. In general components of the polyurethane-forming reaction mixturemay be mixed together in any convenient manner, for example by using anyof the mixing equipment described in the prior art for the purpose suchas described in Polyurethane Handbook, by G. Oertel, Hanser, publisher.

The polyurethane products are either produced continuously ordiscontinuously, by injection, pouring, spraying, casting, calendering;these are made under free rise or molded conditions, with or withoutrelease agents, in-mold coating, or any inserts or skin put in the mold.In case of flexible foams, those can be mono- or dual-hardness.

For producing rigid foams, the known one-shot prepolymer orsemi-prepolymer techniques may be used together with conventional mixingmethods including impingement mixing. The rigid foam may also beproduced in the form of slabstock, moldings, cavity filling, sprayedfoam, frothed foam or laminates with other material such as paper,metal, plastics or wood-board. Flexible foams are either free rise andmolded while microcellular elastomers are usually molded.

The flame resistant polyurethane resin according to this invention ispreferably substantially free of bromine atoms, and more preferablysubstantially free of halogen atoms, as the expression “substantiallyfree” is defined above.

Ignition-Resistant Thermoplastic Resins

In another embodiment of the present invention, thephosphorus-containing product, Compound (I), obtainable by reactingComponent (A) with Component (B) is used to make phosphorus-containingignition resistant thermoplastic resins.

A halogen-free ignition-resistant thermoplastic resin composition areobtainable by blending (i) the phosphorus-containing compound, Compound(I), according to the present invention with (ii) at least onethermoplastic resin.

Typical thermoplastic polymers include, but are not limited to, polymersproduced from vinyl aromatic monomers and hydrogenated versions thereof,including both diene and aromatic hydrogenated versions, includingaromatic hydrogenation, such as styrene-butadiene block copolymers,polystyrene (including high impact polystyrene),acrylonitrile-butadiene-styrene (ABS) copolymers, andstyrene-acrylonitrile copolymers (SAN); polycarbonate (PC), ABS/PCcompositions, polyethylene terephthalate, epoxy resins, hydroxy phenoxyether polymers (PHE) such as those taught in U.S. Pat. Nos. 5,275,853;5,496,910; 3,305,528; ethylene vinyl alcohol copolymers, ethyleneacrylic acid copolymers, polyolefin carbon monoxide interpolymers,chlorinated polyethylene, polyolefins (for example, ethylene polymersand propylene polymers, such as polyethylene, polypropylene, andcopolymers of ethylene and/or propylene with each other or with anα-olefin having at least 4, more preferably at least 6, and preferablyup to 12, and more preferably up to 8, carbon atoms), cyclic olefincopolymers (COC's), other olefin copolymers (especially copolymers ofethylene with another olefin monomer, such as a C₁ to C₁₂ alken-1-ylgroup) and homopolymers (for example, those made using conventionalheterogeneous catalysts), polyphenylene ether polymers (PPO) and anycombination or blend thereof.

Thermoplastic polymers are well-known by those skilled in the art, aswell as methods for making them.

In one embodiment, the thermoplastic polymer is a rubber-modifiedmonovinylidene aromatic polymer produced by polymerizing a vinylaromatic monomer in the presence of a dissolved elastomer or rubber.Vinyl aromatic monomers include, but are not limited to those describedin U.S. Pat. Nos. 4,666,987; 4,572,819 and 4,585,825. Preferably, themonomer is of the Formula (XXXIII):

wherein “R10” is hydrogen or methyl, “Ar¹” is an aromatic ring structurehaving from 1 to 3 aromatic rings with or without alkyl, halo, orhaloalkyl substitution, wherein any alkyl group contains 1 to 6 carbonatoms and haloalkyl refers to a halo-substituted alkyl group.Preferably, “Ar¹” is phenyl or alkylphenyl, wherein alkylphenyl refersto an alkyl substituted phenyl group, with phenyl being most preferred.Typical vinyl aromatic monomers which can be used include, for example,styrene, alpha-methylstyrene, all isomers of vinyl toluene, especiallyparavinyltoluene, all isomers of ethyl styrene, propyl styrene, vinylbiphenyl, vinyl naphthalene, vinyl anthracene, and mixtures thereof. Thevinyl aromatic monomers may also be combined with other copolymerizablemonomers. Examples of such monomers include, but are not limited toacrylic monomers such as acrylonitrile, methacrylonitrile, methacrylicacid, methyl methacrylate, acrylic acid, and methyl acrylate; maleimide,phenylmaleimide, and maleic anhydride, and mixtures thereof.

The rubber used to produce the rubber modified monovinylidene aromaticpolymer can be any rubber which will enhance the impact properties ofthe monovinylidene aromatic polymer, including any moleculararchitecture such as linear, branched, star branched, and homo- andcopolymer diene rubbers, block rubbers, functionalized rubbers, low cis,high cis rubbers and mixtures thereof. The elastomer or rubberpreferably employed are those polymers and copolymers which exhibit asecond order transition temperature which is not higher than 0° C.,preferably not higher than 20° C., and more preferably not higher than40° C. as determined or approximated using conventional techniques, forexample, ASTM test method D 52 T.

The rubber is typically used in amounts such that the rubber-reinforcedpolymer product contains from 3, preferably from 4, more preferably from5 and most preferably from 6 to 20, preferably to 18 percent, morepreferably to 16 and most preferably to 14 weight percent rubber, basedon the total weight of the vinyl aromatic monomer and rubber components,expressed as rubber or rubber equivalent. The term “rubber” or “rubberequivalent,” as used herein, is intended to mean, for a rubberhomopolymer, such as polybutadiene, simply the amount of rubber, and fora block copolymer, the amount of the copolymer made up from monomerwhich when homopolymerized forms a rubbery polymer, such as for abutadiene-styrene block copolymer, the amount of the butadiene componentof the block copolymer.

The rubber is present as discrete rubber particles within themonovinylidene aromatic polymer matrix, and can have any type, includingmonomodal, bimodal or multimodal particle size distribution and particlesize, as well as any morphology including cellular, core shell,onion-skin, as well as any combinations thereof.

Polymerization processes and process conditions for the polymerizationof vinyl aromatic monomers, production of rubber modified polymersthereof and the conditions needed for producing the desired averageparticle sizes, are well known to one skilled in the art. Although anypolymerization process can be used, typical processes are continuousbulk or solution polymerizations as described in U.S. Pat. Nos.2,727,884 and 3,639,372. The polymerization of the vinyl aromaticmonomer is conducted in the presence of predissolved elastomer toprepare impact modified, or grafted rubber containing products, examplesof which are described in U.S. Pat. Nos. 3,123,655; 3,346,520;3,639,522; and 4,409,369, which are incorporated by herein reference.The rubber is typically a butadiene or isoprene rubber, preferablypolybutadiene. Preferably, the rubber modified vinyl aromatic polymer ishigh impact polystyrene (HIPS) or acrylonitrile-butadiene-styrene (ABS),with HIPS being most preferred.

The thermoplastic polymer or polymer blend is employed in thehalogen-free ignition resistant polymer compositions of the presentinvention in amounts of at least 35 parts by weight, preferably at least40 parts by weight, more preferably at least 45 parts by weight, andmost preferably at least 50 parts by weight based on 100 parts by weightof the halogen-free ignition resistant polymer composition of thepresent invention. In general, the thermoplastic polymer component isemployed in amounts less than or equal to 99 parts by weight, preferablyless than or equal to 95 parts by weight, more preferably less than orequal to about 90 parts by weight, and most preferably less than orequal to about 85 parts by weight based on 100 parts by weight of thehalogen-free ignition resistant polymer composition of the presentinvention.

In one embodiment, the halogen-free ignition resistant polymercomposition of the present invention comprises Compound (I) with a blendof two thermoplastic polymers wherein at least one of the thermoplasticpolymers is for example a polyphenylene ether. Polyphenylene ethers aremade by a variety of well known catalytic and non-catalytic processesfrom corresponding phenols or reactive derivatives thereof. By way ofillustration, certain of the polyphenylene ethers useful in the presentinvention are disclosed in U.S. Pat. Nos. 3,306,874; 3,306,875,3,257,357 and 3,257,358.

The polyphenylene ether resins are preferably of the type having therepeating structural Formula (XXXIV):

wherein the oxygen ether atom of one unit is connected to the benzenenucleus of the next adjoining unit, “v” is a positive integer and is atleast 50 and preferably up to about 100,000, and each “Q” is amono-valent substituent selected from the group consisting of hydrogen,halogen, hydrocarbon radicals free of a tertiary alpha carbon atom,halohydrocarbon radicals having at least two carbon atoms between thehalogen atom and the phenyl nucleus, hydrocarbonoxy radicals andhalohydrocarbonoxy radicals having at least two carbon atoms. Thepreferred polyphenylene ether resin is poly(2,6-dimethyl-1,4-phenylene)ether resin.

When used in combination with another thermoplastic polymer, thepolyphenylene ether resin is preferably employed in the halogen-freeignition resistant polymer compositions of the present invention inamounts of at least 5 parts by weight, preferably 10 part by weight,more preferably at least 12 parts by weight, more preferably at least 15parts by weight, and most preferably at least 18 parts by weight to 30parts by weight, preferably to 28 parts by weight, more preferably to 25parts by weight, based on 100 parts by weight of the halogen-freeignition resistant polymer composition of the present invention. Thethermoplastic and polyphenylene ether polymer can be prepared as a blendprior to incorporation into the composition of the present invention, oreach polymer can be incorporated individually.

In one embodiment of the present invention, the ignition resistantthermoplastic polymer composition according to the present invention mayoptionallycontain an epoxidized Compound (I), a benzoxazinering-containing compound or a thermolabile group-containing compoundaccording to the present invention as described above.

In another alternative embodiment of the present invention, the ignitionresistant thermoplastic polymer composition of the present invention maybe a blend of (i) one or more thermoplastic resins and (ii) anepoxidized Compound (I), a benzoxazine-ring containing compound or athermolabile group-containing compound according to the presentinvention as described above.

The composition of the present invention may include other additivessuch as modifiers that include compounds containing functionalitieswhich will enhance the mechanical properties of the composition and arecompatible with the thermoplastic resin. For thermoplastic resins suchas monovinylidene aromatics and conjugated dienes, such functionalitiesmight include, but are not limited to, butadienes, styrene-maleicanhydrides, polybutadiene-maleic anhydride copolymers, carboxylic acidterminated butadienes, and carboxylic acid functionalized polystyrenes.Any combination of modifiers can be used in modifying the phosphoruselement-containing epoxy compounds.

The amount of Compound (I), epoxidized Compound (I), benzoxazine-ringcontaining compound, or thermolabile group-containing compound used inthe ignition resistant thermoplastic polymer composition of the presentinvention is typically at least 1 weight-percent, generally at least 5weight-percent, preferably at least 10, more preferably at least 15, andmost preferably at least 20, weight-percent and less than 50, preferablyless than 45, more preferably less than 40 and most preferably less than35, weight-percent, based on the total weight of the ignition resistantpolymer composition.

Preparation of the ignition resistant polymer composition of the presentinvention can be accomplished by any suitable mixing means known in theart, including dry blending the individual components and subsequentlymelt mixing, either directly in the extruder used to make the finishedarticle or pre-mixing in a separate extruder. Dry blends of thecompositions can also be directly injection molded without pre-meltmixing.

When softened or melted by the application of heat, the ignitionresistant thermoplastic polymer composition of this invention can beformed or molded using conventional techniques such as compressionmolding, injection molding, gas assisted injection molding, calendaring,vacuum forming, thermoforming, extrusion and/or blow molding, alone orin combination. The ignition resistant thermoplastic polymer compositioncan also be formed, spun, or drawn into films, fibers, multi-layerlaminates or extruded sheets, or can be compounded with one or moreorganic or inorganic substances, on any machine suitable for suchpurpose.

In one embodiment, the composition of the present invention can beutilized in the preparation of a foam. The ignition resistant polymercomposition is extruded into foam by melt processing it with a blowingagent to form a foamable mixture, extruding said foamable mixturethrough an extrusion die to a region of reduced pressure and allowingthe foamable mixture to expand and cool. Conventional foam extrusionequipment, such as screw extruders, twin screw extruders andaccumulating extrusion apparatus can be used. Suitable processes formaking extruded foams from resin/blowing agent mixtures are described inU.S. Pat. Nos. 2,409,910; 2,515,250; 2,669,751; 2,848,428; 2,928,130;3,121,130; 3,121,911; 3,770,688; 3,815,674; 3,960,792; 3,966,381;4,085,073; 4,146,563; 4,229,396; 4,302,910; 4,421,866; 4,438,224;4,454,086 and 4,486,550.

In another embodiment of the present invention, the halogen-freeignition resistant polymer composition of the present invention mayoptionally include, in addition to Compound (I), otherphosphorus-containing compounds. Optionally, the composition of thepresent invention may also include other flame retardant additives whichcan be phosphorus or non-phosphorus materials as described above.

The amount of optional phosphorus-containing compounds, other thanCompound (I), and/or the optional flame retardant additives used in thecomposition of the present invention may be from 0 up to 30 weightpercent. The amount of optional phosphorus-containing component, otherthan Compound (I), when present, is preferably at least 1 weight-percentand preferably up to 30 weight-percent based on the total weight of thethermoplastic resin.

The amount of component, Compound (I), is preferably at least 5weight-percent and preferably up to 20 weight-percent, based on thetotal weight of the thermoplastic resin.

The ignition resistant thermoplastic resin is preferably substantiallyfree of bromine atoms, and more preferably substantially free of halogenatoms, as the expression “substantially free” is defined above.

The halogen-free ignition resistant polymer compositions of the presentinvention are useful to fabricate numerous useful articles and parts.Some of the articles which are particularly well suited includetelevision cabinets, computer monitors, related printer housings whichtypically requires to have excellent flammability ratings. Otherapplications include automotive and small appliances.

Ignition-Resistant Thermosetting Composition

In another embodiment of the present invention, thephosphorus-containing product, Compound (I), obtainable by reactingComponent (A) with Component (B) is used to make phosphorus-containingignition resistant thermosetting composition.

A halogen-free ignition-resistant thermosetting composition isobtainable by blending (i) the phosphorus-containing compound, Compound(I), according to the present invention with (ii) at least onethermosetting system. Examples of thermosetting systems are epoxy,polyurethane, polyisocyanates, benzoxazine ring-containing compounds,unsaturated resin systems containing double or triple bonds, polycyanateester, bismaleimide, triazine, bismaleimide and mixtures thereof.

In another embodiment of the present invention, the ignition resistantthermosetting polymer composition according to the present invention mayoptionally contain an epoxidized Compound (I), a benzoxazinering-containing compound or a thermolabile group-containing compoundaccording to the present invention as described above.

In another alternative embodiment of the present invention, the ignitionresistant thermosetting polymer composition of the present invention maybe a blend of (i) one or more thermosetting systems and (ii) anepoxidized Compound (I), a benzoxazine ring containing compound or athermolabile group containing compound according to the presentinvention as described above.

Ignition-Resistant Thermoplastic/Thermosetting Hybrid Systems

In another embodiment of the present invention, thephosphorus-containing product, Compound (I), obtainable by reactingComponent (A) with Component (B) is used to make phosphorus-containingignition resistant hybrid resin system that contains both athermoplastic and a thermosetting system.

The hybrid ignition-resistant thermoplastic and thermosettingcompositions are obtainable by blending (i) the phosphorus-containingcompound, Compound (I), according to the present invention with (ii) athermoplastic resin and (iii) a thermosetting system. Examples ofthermoplastic resins are polyphenylene oxide (PPO), mixtures thereof,and others as described in the above paragraph. Examples ofthermosetting systems are epoxy, polyurethane, polyisocyanates,benzoxazine ring-containing compounds, unsaturated resin systemscontaining double or triple bonds, polycyanate ester, bismaleimide,triazine, bismaleimide and mixtures thereof.

In another embodiment of the present invention, the ignition resistantthermoplastic/thermosetting hybrid polymer composition according to thepresent invention may optionally contain an epoxidized Compound (I), abenzoxazine ring-containing compound or a thermolabile group-containingcompound according to the present invention as described above.

In another alternative embodiment of the present invention, the ignitionresistant thermoplastic/thermosetting hybrid polymer composition of thepresent invention may be a blend of (i) one or more thermoplasticresins, (ii) one or more thermosetting systems and (iii) an epoxidizedCompound (I), a benzoxazine ring-containing compound or a thermolabilegroup-containing compound according to the present invention asdescribed above.

The compositions described above are useful for making coatingformulations, encapsulation, composites, adhesives, molding, bondingsheets, laminated plates. As an illustration, a coating formulation maycomprise (i) Compound (I), (ii) a solid epoxy resin, and (iii) ahardener such as an amine or phenolic hardener.

The following examples illustrate how one may practice the presentinvention. Those who are skilled in this field of technology are capableof practicing the full scope of the present invention via proceduresanalogous to those described below.

EXAMPLES

The materials used in the examples are described below:

Designation Description Struktol3,4,5,6-dibenzo-1,2-oxaphosphane-2-oxide, available Polydis ™ PD fromSchill & Seilacher GmbH & Co., a company 3710 incorporated in GermanySANTOLINK Butyl etherified phenol and formaldehyde EP 560 condensationproduct, available from UCB Group, a company headquartered in Brussels,Belgium, and its affiliate, UCB GmbH & Co. KG, a company incorporated inGermany PHENODUR Butyl etherified phenol and formaldehyde VPR 1785/50condensation product with a weight average molecular weight from 4000 to6000 and a polydispersity from 2 to 3, available from UCB Group, acompany headquartered in Brussels, Belgium, and its affiliate, UCB GmbH& Co. KG, a company incorporated in Germany PHENODUR Butyl etherifiedbisphenol A and formaldehyde PR 411 condensation product, available fromUCB Group, a company headquartered in Brussels, Belgium, and itsaffiliate, UCB GmbH & Co. KG, a company incorporated in Germany D.E.N.438 Liquid epoxy novolac resin having an epoxide equivalent weight ofabout 180, available from The Dow Chemical Company, a U.S. corporation.DICY Dicyandiamide Phenol novolac Condensation products obtained fromphenol and resin formaldehyde having a softening point of 95-100° C. and6-7 hydroxyl group functionality SMA Styrene maleic anhydride having 20weight-percent percent maleic anhydride content MEK Methyl ethyl ketone(an organic solvent) DMF Dimethyl formamide (a reactive solvent) DOWANOLMethoxypropylacetate, available from The Dow PMA Chemical Company. Glasscloth Glass cloth reinforcement, available from Porcher reinforcementTextile, Badinieres, Bourgoin-Jallieu, France Type 7628 Amino silane Aglass sizing, available from Porcher Textile, finish 731 Badinieres,Bourgoin-Jallieu, France

The test procedures used to measure the properties of the variousmaterials of the examples are further described below:

Property Measured Measurement Procedure TMA Thermo-mechanical analysisvia IPC-TM-650-#2.4.24C T-288 Time to delamination at 288° C. measuredby TMA via method IPC-TM-650-#2.4.24:1 Tg Glass transition temperaturemeasured in degrees Celsius according to IPC-TM-650-2.4.25 UL 94Flammability test according to IPC-TM-650-2.3.10 Flammability CTE <Tg/>Tg Coefficient of thermal expansion below Tg and after Tg HPCT Highpressure cooker test reporting weight percent water pick-up & percentpassed solder bath @ 260 C. according to IPC-TM-650-2.6.16 Cu peel, N/cmCopper peel strength measured using the method described inIPC-TM-650-#2.4.8C V_(O) rating Rating used in the UL 94 Flammabilitytest.

The IPC test methods are the electrical laminate industry standardsdeveloped by The Institute For Interconnection And Packaging ElectronicCircuits, 3451 Church Street, Evanston, Ill. 60203.

Preparation of phosphorus-containing compounds according to the presentinvention is illustrated by the following examples.

Example 1 Preparation A

24.69 Grams (gm) of SANTOLINK EP 560 was mixed with 30 gm of StruktolPolydis™ PD 3710 at 170° C. for 10 minutes and heated to 190° C. in 5minutes and the mixture was held at 190° C. for 20 minutes. Theresulting reaction product was placed in a vacuum oven for an additional30 minutes at 160° C. to complete the reaction by driving out butanol.The weight of the resultant final solid was about 45.6 grams.

The resultant product had a melt viscosity @ 150° C. of 16 Pa·s, and aTg equal to 78° C. The theoretical phosphorus content of the product wasabout 9.21 weight percent.

Example 2 Preparation B

480 gm of solid Struktol Polydis™ PD 3710 and 640 gm of Phenodur VPR1785 (50 percent solid in methoxy propanol) were charged in a 1-literglass reactor equipped with a mechanical stirrer and a heating jacket,and fitted with a nitrogen gas inlet, a condenser and a solventcollector. The mixture was heated to 120° C. under nitrogen atmosphereto obtain a homogeneous mixture. The homogeneous reaction mixture washeated 1 degree Celsius per minute from 120° C. to 205° C. The solvent(from VPR 1785) and butanol were collected stepwise when the temperaturewas raised. The reaction mixture was held at 205° C. for 30 minutesuntil no further volatiles were released from the reaction mixture. Theresultant solid material was taken out from the reactor. The totalweight of the solid material was 757.8 grams, its Tg was 88° C., and itstheoretical phosphorus content was about 8.87 weight percent.

Examples 3-5

The formulations in the table below were prepared with the product ofPreparation A described in Example 1 above.

Curable Formulations Based on Preparation A

Example 3 Example 4 Example 5 (Formulation (Formulation (Formulation 1)2) 3) Component D.E.N. 438 (85 weight. percent in MEK) 67 30 55 (partsby weight based on solids) Product of Preparation A (60 wt. percent in33 35 27 MEK) (parts by weight based on solids) DICY (20 wt. percent inDMF) (parts by 2 0 0 weight based on solids) Phenol novolac (50 wt.percent in 0 0 18 DOWANOL PMA) (parts by weight based on solids) SMA(parts by weight based on solids) 0 35 0 Boric acid (20 wt. percent inmethanol) (parts 0.6 0.6 0.6 by weight based on solids)2-phenylimidazole (20 wt. percent in 1.5 0 0.6 DOWANOL PMA) (parts byweight based on solids) 2-ethyl, 4-methyl imidazole (20 wt. percent in 00.2 0 DOWANOL PMA) (parts by weight based on solids) Properties Gel timeat 170° Celsius in seconds 182 264 220 Glass transition temperature (Tg)in degrees 170 166 171 Celsius

For each Formulation 1, 2, and 3, the above components were combined andmixed at room temperature (˜25° C.) for about 60 minutes to form avarnish suitable for the measurement of gel time and glass transitiontemperature of the cured products.

Example 6

Formulation 1 described in Example 3 above was impregnated into a glasscloth reinforcement substrate having amino silane finish 731. Theimpregnated substrate is passed through a CARATSCH pilot treater (builtby Caratsch AG, Bremgarten, Switzerland) having a 3 meter horizontaloven at an air temperature of approximately 177° C. and a winding speedof 1.4 meters per minute to form a prepreg. The resulting prepreg had aresin content of about 34.5 wt. percent and a residual gel time of 145seconds at 171° C.

The prepreg formed above was cut into eight samples (30 cm×30 cmsamples) and then a laminate was formed from the prepreg samples asfollows: eight layers of prepregs together with two layers of copperwere pressed together at 190° C. for 90 minutes to obtain a laminatehaving a TMA thickness of about 1.48 mm The laminate had a TMA Tg ofabout 163° C., a CTE<Tg/>Tg of 40.2/241.9, and a T-288 greater than 60minutes. The copper peel strength of the laminate was about 14.3 N/cm.The laminate passed the UL 94 Flammability Vo rating.

Example 7 Preparation C

440 gm of solid Struktol Polydis™ PD 3710 and 720 gm of Phenodur VPR1785 (50 percent solid in methoxy propanol) were charged in a 1-literglass reactor equipped with a mechanical stirrer and a heating jacket,and fitted with a nitrogen gas inlet, a condenser and a solventcollector. The mixture was heated from 100 degree Celsius to 201° C. in155 min The solvent (from VPR 1785) and butanol were collected stepwisewhen the temperature was raised. The reaction mixture was held at 201°C. for 40 minutes until no further volatiles were released from thereaction mixture. The resultant solid material was taken out from thereactor. The Tg was 104° C., and the melt viscosity at 200° C. is 2.34Pas.

The resulting product of this example is believed to be a blend ofoligomers wherein one of the oligomers has the following structure:

Example 8 Preparation D

558.3 gm of solid Struktol Polydis™ PD 3710 and 391.6 gm of Phenodur PR411 (75 percent solid in butanol) were charged in a 1-liter glassreactor equipped with a mechanical stirrer and a heating jacket, andfitted with a nitrogen gas inlet, a condenser and a solvent collector.The mixture was heated from 96 degree Celsius to 199° C. in 180 minButanol were collected stepwise when the temperature was raised. Thereaction mixture was held at 200° C. for 20 minutes until no furthervolatiles were released from the reaction mixture. The resultant solidmaterial was taken from the reactor. The Tg measured by DSC was about108.5° C.

The resulting product of this example is believed to be a blend ofoligomers wherein one of the oligomers has the following structure:

Example 9 Preparation E

405.5 gm of solid Struktol Polydis™ PD 3710 and 391.6 gm of Phenodur PR411 (75 percent solid in butanol) were charged in a 1-liter glassreactor equipped with a mechanical stirrer and a heating jacket, andfitted with a nitrogen gas inlet, a condenser and a solvent collector.The mixture was heated from 106 degree Celsius to 155° C. in 95 minButanol were collected stepwise when the temperature was raised. Thereaction mixture was held at 155° C. for 300 minutes until no furthervolatiles were released from the reaction mixture. The resultant solidmaterial was taken from the reactor. The Tg measured by DSC was about138° C.

1-7. (canceled)
 8. A homogeneous solution, comprising: dicyandiamide;and a phenolic hardener having the general formula:

where R′ and R″ may be the same or different and each represents R- orRO-radicals, with R being an alkyl or aromatic radical; R′″ is hydrogen,an alkyl or aromatic radical, —CH₂P(O)R′R″, or —CH₂OR; n is a wholenumber within the range from 0 to 100, wherein said dicyandiamide is notdissolved in a solvent selected from the group consisting ofdimethylformamide, N-methylpyrodinone, dimethylsulfoxide, andcombinations thereof and wherein the homogeneous solution does notcontain an epoxy resin.
 9. The solution of claim 8 further comprising asolvent comprising at least one of an alcohol, a ketone, and a glycolether.
 10. The solution of claim 9, wherein the alcohol comprises abutanol.
 11. The solution of claim 9, wherein the ketone comprisesmethyl ethyl ketone.
 12. The solution of claim 9, wherein the glycolether comprises propylene glycol methyl ether.
 13. The solution of claim8, further comprising an imidazole catalyst.
 14. The solution of claim8, further comprising at least one additional hardener selected from thegroup consisting of a phenol novolac, a bisphenol A novolac, and acresol novolac.
 15. The solution of claim 9, wherein the solutioncomprises: 1 to 60 weight percent of the phenolic hardener; 1 to 20weight percent of the dicyandiamide; and 5 to 30 weight percent of thesolvent; wherein the weight percentages given are based on the combinedweight of the phenolic hardener, the dicyandiamide, and the solvent. 16.A curable composition, comprising the solution of claim 8 and an epoxyresin.
 17. The curable composition of claim 16, wherein the compositioncomprises: 30 to 99 weight percent of the epoxy resin, 0.01 to 5 weightpercent of the dicyandiamide; 1 to 40 weight percent of the phenolichardener; and 0 to 30 weight percent of a solvent comprising at leastone of an alcohol, a ketone, and a glycol ether; wherein the weightpercentages given are based on the combined weight of the phenolichardener, the dicyandiamide, the epoxy resin, and the solvent.
 18. Thecurable composition of claim 16, wherein the epoxy resin comprises anepoxy terminated polyoxazolidone-containing compound.
 19. The curablecomposition of claim 18, wherein the epoxy terminatedpolyoxazolidone-containing compound comprises a reaction product of apolyepoxide compound and a polyisocyanate compound.
 20. A process forforming a dicyandiamide hardener composition, comprising: admixingdicyandiamide and a phenolic hardener having the general formula:

where R′ and R″ may be the same or different and each represents R- orRO-radicals, with R being an alkyl or aromatic radical; R′″ is hydrogen,an alkyl or aromatic radical, —CH₂P(O)R′R″, or —CH₂OR; n is a wholenumber within the range from 0 to 100 wherein said dicyandiamidehardener does not contain a solvent selected from the group consistingof dimethylformamide, N-methylpyrodinone, dimethylsulfoxide andcombinations thereof and wherein the hardener does not contain an epoxyresin.
 21. The process of claim 20, further comprising admixing asolvent comprising at least one of an alcohol, a ketone, and a glycolether with at least one of the dicyandiamide and the phenolic hardener.22. The process of claim 20, further comprising admixing an epoxy resinwith the hardener composition to form a curable composition.
 23. Theprocess of claim 22, further comprising curing the curable compositionto form a thermoset resin.